Mukun He, Xiao Zhong, Xinghan Lu, Jinwen Hu, Kunpeng Ruan, Hua Guo, Yali Zhang, Yongqiang Guo* and Junwei Gu*. Excellent Low-frequency Microwave Absorption and High Thermal Conductivity in Polydimethylsiloxane Composites Endowed by Hydrangea-like CoNi@BN Heterostructure Fillers. Advanced Materials, 2024, 36: 2410186. 2023IF=27.4
https://doi.org/10.1002/adma.202410186
Abstract
The advancement of thin, lightweight, and high-power electronic devices has increasingly exacerbated issues related to electromagnetic interference and heat accumulation. To address these challenges, we employed a spray-drying-sintering process to assemble chain-like CoNi and flake boron nitride (BN) into hydrangea-like CoNi@BN heterostructure fillers. These fillers were then composited with polydimethylsiloxane (PDMS) to develop CoNi@BN/PDMS composites, which integrate low-frequency microwave absorption and thermal conductivity. When the volume fraction of CoNi@BN is 44 vol% and the mass ratio of CoNi to BN is 3:1, the CoNi@BN/PDMS composites exhibit optimal performance in both low-frequency microwave absorption and thermal conductivity. These composites achieve a minimum reflection loss of -49.9 dB and a low-frequency effective absorption bandwidth of 2.40 GHz (3.92~6.32 GHz) at a thickness of 4.4 mm, fully covering the n79 band (4.4~5.0 GHz) for 5G communications. Meanwhile, the in-plane thermal conductivity (λ∥) of the CoNi@BN/PDMS composites is 7.31 W m-1 K-1, which is about 11.4 times of the λ∥ (0.64 W m-1 K-1) for pure PDMS, and 32% higher than that of the (CoNi/BN)/PDMS composites (5.52 W m-1 K-1) with the same volume fraction of CoNi and BN obtained through direct mixing.
電子設備的輕薄化和高功率化發展，導致其電磁干擾和熱量聚集問題愈發嚴重。本文采用“噴霧干燥-燒結”工藝將鏈狀CoNi和片狀BN組裝為繡球花狀CoNi@BN異質結構填料，再將其與聚二甲基硅氧烷（PDMS）復合制備低頻吸波/導熱一體化CoNi@BN/PDMS復合材料。當CoNi@BN的體積分數為44 vol%且CoNi與BN質量比為3:1時，CoNi@BN/PDMS復合材料兼具最優的低頻吸波性能和導熱系數，厚度為4.4 mm時最小反射損耗（RLmin）為-49.9 dB、低頻有效吸收帶寬（EAB）為2.40 GHz（3.92~6.32 GHz），完全覆蓋5G通訊涉及的n79（4.4~5.0 GHz）頻段，其面內導熱系數（λ∥）為7.31 W m-1 K-1，約為純PDMS的λ∥（0.64 W m-1 K-1）的11.4倍，較相同CoNi和BN體積分數且直接共混的(CoNi/BN)/PDMS復合材料的λ∥（5.52 W m-1 K-1）提高了32%。
論文亮點
1. 采用“噴霧干燥-燒結”工藝將一維鏈狀CoNi和二維片狀BN組裝成繡球花狀CoNi@BN異質結構填料。當CoNi與BN質量比為3:1時，CoNi@BN具有優異的阻抗匹配和低頻吸波性能。
2. 當CoNi@BN的體積分數為44 vol%時，4.4 mm的CoNi@BN/PDMS復合材料RLmin為-49.9 dB、低頻EAB為2.40 GHz（3.92~6.32 GHz），完全覆蓋了5G的n79頻段（4.4~5.0 GHz）。
3. 當CoNi@BN的體積分數為44 vol%時，CoNi@BN/PDMS復合材料的λ∥為7.31 W m-1 K-1，約為純PDMS的λ∥（0.64 W m-1 K-1）的11.4倍，較相同CoNi和BN體積分數且直接共混的(CoNi/BN)/PDMS復合材料的λ∥（5.52 W m-1 K-1）提高了32%。
第一作者：何沐錕
郵箱地址：hemukun@mail.nwpu.edu.cn